; world cup prognostication

(define sort #f)
(define merge #f)
(let ()

; Mardi Gras

; Easter occurs each year on the first Sunday after the first full moon after
; the vernal equinox.  Mardi Gras occurs on the Tuesday of the seventh week
; before Easter.  This program calculates the date of Mardi Gras.

(define (primes n)
  (let* ((max-index (quotient (- n 3) 2)) (v (make-vector (+ 1 max-index) #t)))
    (let loop ((i 0) (ps '(2)))
      (let ((p (+ i i 3)) (startj (+ (* 2 i i) (* 6 i) 3)))
        (cond ((>= (* p p) n)